Magnetostriction of field-structured magnetoelastomers.

Gulley, Gerald L. (Dominican University, River Forest, IL) ; Read, Douglas H. ; Martin, James Ellis ; Huber, Dale L. ; Anderson, Robert Alan ; Frankamp, Benjamin L.

Sandia National Laboratories

关键词: Magnetic Fields.;    Magnetosphere.;    Magnetostriction;    Actuators;    36 Materials Science;   

DOI  :  10.2172/877143
RP-ID  :  SAND2005-8032
RP-ID  :  AC04-94AL85000
RP-ID  :  877143

美国|英语

来源: UNT Digital Library

【 摘 要 】

Field-structured magnetic particle composites are an important new class of materials that have great potential as both sensors and actuators. These materials are synthesized by suspending magnetic particles in a polymeric resin and subjecting these to magnetic fields while the resin polymerizes. If a simple uniaxial magnetic field is used, the particles will form chains, yielding composites whose magnetic susceptibility is enhanced along a single direction. A biaxial magnetic field, comprised of two orthogonal ac fields, forms particle sheets, yielding composites whose magnetic susceptibility is enhanced along two principal directions. A balanced triaxial magnetic field can be used to enhance the susceptibility in all directions, and biased heterodyned triaxial magnetic fields are especially effective for producing composites with a greatly enhanced susceptibility along a single axis. Magnetostriction is quadratic in the susceptibility, so increasing the composite susceptibility is important to developing actuators that function well at modest fields. To investigate magnetostriction in these field-structured composites we have constructed a sensitive, constant-stress apparatus capable of 1 ppm strain resolution. The sample geometry is designed to minimize demagnetizing field effects. With this apparatus we have demonstrated field-structured composites with nearly 10,000 ppm strain.